Windows 3.1x (codenamed Janus) is a series of 16-bit operating systems produced by Microsoft for use on personal computers. The series began with Windows 3.1, which was first sold during April 1992 as a successor to Windows 3.0. Subsequent versions were released between 1992 and 1994 until the series was superseded by Windows 95. During its lifespan, Windows 3.1 introduced several enhancements to the still MS-DOS-based platform, including improved system stability, expanded support for multimedia, TrueType fonts, and workgroup networking.
Windows 3.1 was originally released on April 6, 1992; official support for Windows 3.1 ended on December 31, 2001.
Windows 3.1 was designed to have backward compatibility with older Windows platforms. As with Windows 3.0, version 3.1 had File Manager and Program Manager, but unlike all previous versions, Windows 3.1 cannot run in real mode. It included Minesweeper as a replacement for Reversi (though Reversi was still included in some copies).
Windows 3.1 Multimedia PC Version (Beta only, released Nov 1992 – codenamed Bombay) included a media viewer, and the ability to play video files. It was targeted to the new multimedia PC and included sound and video integration with CD-ROM support.
Windows 3.1 dropped real mode support and required a minimum of a 286 PC with 1 MB of RAM to run. The effect of this was to increase system stability over the crash-prone Windows 3.0. Some older features were removed, like CGA graphics support (although Windows 3.0's CGA driver still worked on 3.1) and compatibility with real mode Windows 2.x applications.
Truetype font support was added, providing scalable fonts to Windows applications, without having to resort to using a third-party font technology such as Adobe Type Manager. Windows 3.1 included the following fonts: Arial, Courier New, Times New Roman, and Symbol (a collection of scalable symbols) in regular, bold, italic, and bold-italic versions. Truetype fonts could be scaled to any size and rotated, depending on the calling application.
In 386 Enhanced Mode, windowed DOS applications gained the ability for users to manipulate menus and other objects in the program using the Windows mouse pointer, provided that DOS application supported mice. A few DOS applications such as late releases of Microsoft Word could access Windows Clipboard. Windows' own drivers couldn't work directly with DOS applications; hardware such as mice required a DOS driver to be loaded before starting Windows.
Icons could be dragged and dropped for the first time, in addition to having a more detailed appearance. A file could be dragged onto Print Manager icon and the file would be printed by the current printer, assuming it was associated with an application capable of printing, such as a word processor. Alternatively, the file could be dragged out of File Manager and dropped onto an application icon or window for processing.
While Windows 3.0 was limited to 16 MB maximum memory, Windows 3.1 can access a theoretical 4 GB in 386 Enhanced Mode. (The actual practical ceiling is 256 MB.) However, no single process can use more than 16 MB. File Manager was significantly improved over Windows 3.0. Multimedia support was enhanced over what was available in Windows 3.0 with Multimedia Extensions and available to all Windows 3.1 users.
Windows 3.1 was available via 720 KB, 1.2 MB, and 1.44 MB floppy distributions. It was also the first version of Windows to be distributed on CD-ROM — although this was more common for Windows for Workgroups 3.11, which typically came with MS-DOS 6.22 on one CD. Installed size on the hard disk was between 10 MB and 15 MB.
32-bit disk access (386 Enhanced Mode only) brought improved performance by using a 32-bit protected mode driver instead of the 16-bit BIOS functions (which necessitate Windows temporarily dropping out of protected mode).
Windows 3.1's calendar saves its files ending with .cal.
Windows 3.1 also introduced Windows Registry, a centralized database that can store configuration information and settings for various operating systems components and applications.
Windows 3.1 was the first version of Windows that could also launch Windows programs via Command.com while running Windows.
Microsoft began a television advertising campaign for the first time on March 1, 1992. The advertisements, developed by Ogilvy & Mather, were designed to introduce a broader audience to Windows. Windows 3.1 was shipped worldwide on April 6, 1992, and reached three million sales two months later. The year of Windows 3.1's release was successful for Microsoft, which was named the "Most Innovative Company Operating in the U.S." by Forbes magazine, while Windows became the most widely used GUI-based operating environment.
Windows 3.x was superseded by the release of Windows 95 in August 1995. Microsoft officially dropped support for all 16-bit versions of Windows on December 31, 2001.
Windows 3.1 found a niche market as an embedded operating system after becoming obsolete in the PC world. As of November 2008, both Virgin Atlantic and Qantas employed it for some of the onboard entertainment systems on long-distance jets. It also sees continued use as an embedded OS in retail cash tills. It is also used as a secondary application in DOSBox to enable emulation of Win16 games on 64-bit Windows.
On July 9, 2008, it was announced that Windows for Workgroups 3.11 for the embedded devices channel would no longer be made available for OEM distribution as of November 1, 2008.
On July 14, 2013, Linux kernel 3.11 was officially named "Linux For Workgroups" as a tongue-in-cheek reference to "Windows for Workgroups 3.11".
On November 7, 2015, Orly Airport near Paris, France, had a major computer glitch that interrupted its operations for some time. The newspaper Le Canard Enchaîné later revealed that the glitch happened in an essential meteorological system called DECOR, which at the time of the incident still ran on Windows 3.1 – 23 years after the operating system's release and 14 years after Microsoft ceased to support it. The French Transportation Minister promised to have the system replaced by 2017, but the secretary general of the French air traffic controller union expressed his skepticism.